Patients suffering from wheat-related troubles, in absence of celiac disease or wheat allergy diagnosis, can suffer from non-celiac wheat sensitivity (NCWS). This is characterized by both gastrointestinal (GI) and extra-intestinal symptoms, which improve with the elimination of wheat intake. To date no definitive explanation of pathogenetic mechanisms of NCWS has been proved, and, similarly, no specific non-invasive diagnostic biomarker has been recognized. A real need of strict adherence to wheat-free diet (WFD) in NCWS has never been demonstrated. In this context, research is actively trying to find wheat varieties with absent or low immune-reactivity to be used for the treatment of NCWS patients. Preliminary evidence supports the assumption that diploid wheat species, as Triticum monococcum (TM), compared to common ones (Triticum aestivum (TA), could possess a lower immunogenic potential in NCWS patients. The first objective of our project is to verify whether the use of a diploid wheat (TM), with a lower concentrations and bioactivity of Amylase-Trypsin-Inhibitors (ATIs) and with gliadin proteins with a better digestibility, compared to a hexaploid one (TA) could improve both symptoms and quality of life (QoL) of NCWS subjects. The second objective is the identification of non-invasive serological biomarkers for NCWS diagnosis. The third objective is to identify T cell lymphocytes able to recognize cognate peptides from wheat proteins to better classify and monitor patients affected by NCWS. To achieve these results we planned a prospective, double-blind clinical trial with crossover, in which patients already diagnosed with NCWS (according to international criteria and with a double-blind placebo-controlled wheat challenge), following a strict WFD, will be exposed in double-blind to both TM and TA. All the patients will be evaluated clinically at the different timepoints with validated scales to assess tolerability of TM. Moreover, their intestinal permeability, immunological activation and gut microbiota patterns will be studied by both in vitro and in vivo techniques. Finally, a randomly chosen subset of patients will be studied through single cell transcriptome and T-cell receptor (TCR) sequencing on rectoscopy biopsy specimens to identify, T cell lymphocytes able to recognize cognate peptides from wheat proteins.